Long-term predictors of outcome in Brugada syndrome patients after implantable cardioverter-defibrillator implant

Various clinical risk factors impact the natural history of Brugada syndrome (BrS) and establish the basis of current clinical practice guidelines (CPG) indications for implantable cardioverter-defibrillator (ICD). Due to the time-dependent expressivity of BrS, their performance in predicting the actual occurrence of arrhythmic events after ICD implantation remains unknown.

To assess the occurrence of arrhythmic events based on the CPG indications and whether the genetic substrate can add to the prediction of arrhythmic events at follow-up.

We enrolled consecutive patients who underwent ICD implant either for primary or secondary prevention. Prospective clinical data included arrhythmic history, electrocardiographic findings, therapies, SCN5A gene mutations, and genotyping of three BrS-associated single nucleotide variants. Eleven per cent of 551 patients experienced life-threatening arrhythmic events (LAE) over a median follow-up of 8.1 years. Patients with ESC class IIA indication had a similar risk profile as those implanted for secondary prevention. The recently developed BrS 5-year risk score, including clinical and genetic variables, was a determinant of outcome in the whole cohort and in patients implanted for primary prevention: 26.93 ± 3.33 vs. 4.41 ± 0.61 and 11.67 ± 1.52 vs. 5.36 ± 0.99 in patients with LAEs compared with those without events (P < 0.0001).

CPG class IIa and I had a similar rate of ICD shock at follow-up. We also provide robust evidence indicating that the quantification of the BrS arrhythmic risk score at the moment of ICD implant may improve the identification of patients who will benefit from ICD at follow-up.